This invention relates to a method and apparatus for the detection and/or measurement of a condition that affects the color of a test subject, and more particularly to a process and instrument for measuring at least one color characteristic or factor of a test subject indicative of the condition of interest such as biological condition or hair coloration.
Visual observation of a subject for changes in coloration indicative of a particular condition has often occurred. The subject may be a person or animal being observed to determine the presence or absence of a medical condition. The color characteristics or a single color characteristic of other test subjects such as biopsy specimens or excretions have diagnostic value.
An individual person""s skin color is often assessed by her or his doctor. Hypertension, tuberculosis, sclerosis of the liver, to name just a few, are examples of ailments with symptomatic skin color changes among at least a sizeable population segment. Hair color evaluation and dental coloration evaluation are valuable. These may bear on the health of the individual, or on the health of the individual""s hair and teeth, or these may permit accurate cosmetic activities, for example, to counteract graying or to accurately match new dental work to existing teeth.
Likewise, the condition of plants and agricultural products is visually inspected for color as an indication of condition. Contamination of soil is likewise apparent from visual inspection. Such visual inspections are subjective. Measuring by instrument the color characteristics that are key to the visual inspection has the benefit of objectivity and consistency.
In the past, hyperbilirubinemia in newborns has been detected by visually observing an individual for jaundice or by routinely taking and testing a blood sample. Upon detection, hyperbilirubinemia has been treated by phototherapy. During the course of phototherapy, blood samples have been taken and tested at regular intervals until it was determined that the level of serum bilirubin had decreased to an acceptable level.
In infants, there is little blood available for use in the blood testing for hyperbilirubinemia. So much blood is drawn that transfusions are often necessary to replace the drawn blood. The newborn is thereby exposed to all of the risks that transfusions bring. Blood sampling and transfusions are, of course, painful to the newborn, and as with any invasive procedure, both present medical risks, such as for example, risk of infection. There is a need, therefore, for a reliable, noninvasive technique for detecting and measuring a skin color affecting medical condition such as hyperbilirubinemia.
This is one example of a wider need for procedures and instruments to objectively and consistently determine a color characteristic or factor indicative of the condition of a test subject or indicative of a particular ailment or condition. The methods and apparatus of this invention can be employed where previously visual inspection, of which examples are given above, have been carried out at least in part on the basis of observable color characteristics.
This invention also relates to a method and apparatus for the categorizing of hair color and hair color treatment agents for their interrelationship, and more particularly to a process and instrument for measuring three color characteristics of hair color and categorizing it and determining the effect of a wide variety of hair coloring agents thereon.
Hair coloring agent choices are often made by a consumer based on relatively vague indications of the color to be expected as a result of the use of the agent on an individual person""s hair. This approach does not take into consideration the color of the hair that is to be treated and how interaction of that particular individual""s hair color with the coloring agent will affect the resultant color.
No reliable source of information has been available to a private consumer regarding what the actual color of her or his hair is and what hair coloring agent will provide the hair color alteration that consumer seeks.
Consequently it can be seen there exists a need for procedures and apparatus that will accurately characterize an individual""s hair color to enable selection of appropriate coloring agents for a desired color result. Likewise there exists a need for a reliable process and instrumentation to permit the use of the accurate color characterization of an individual""s hair color in the selection of hair coloring agents to effect hair color alterations of a type desired by the individual.
According to this invention there is provided a method and apparatus for detecting and quantitatively measuring a condition affecting the color of a test subject. The method includes measuring at least one color characteristic of the subject.
In one exemplary procedure according to this invention at least one skin color characteristic is measured at least at first and second points in time. To test for hyperbilirubinemia, the two measurements are then compared for change. In the preferred procedure a second skin color characteristic is also measured on the basis of which the subject can be assigned to one of plural categories among which varying amounts of change in the first-mentioned skin color characteristic are indicative of the presence of a medical condition. The first characteristic is then observed for a change of measured value sufficient to indicate the medical condition for a subject in that category. Preferably, a base reading of at least the first color characteristic is first made at a time the subject is without characteristic skin coloration indicative of the medical condition for which he or she is to be tested.
In the case of hyperbilirubinemia detection, the first skin color characteristic is Hunter b, which is a color factor dependent on the relative content, in a color, of two opponent colors, yellow and blue. Hunter b is a factor comprising a first function (Y) weighted in a first portion of the spectrum, the yellower portion, a second function (Z) weighted in a second portion of the spectrum, the bluer portion, and a weighting term (1/Yxc2xd) that is a function of the lightness of a color and that decreases the value of the color factor as lightness increases. Y and Z are part of the three tristimulus values X, Y and Z known to the color scientist for the purpose of defining a color. They are measurable by commercially available instruments such as colorimeters.
In the case of testing newborns for hyperbilirubinemia, readings of Hunter b and the Hunter lightness measure L are made shortly after birth. These can provide the base reading since hyperbilirubinemia does not manifest itself immediately after birth. The first reading is preferably made within five hours, but as soon as possible after birth. Subsequent readings are then made during the next few days. The subsequent readings of Hunter b are compared with the first, baseline reading of Hunter b to determine whether Hunter b has increased to an extent that indicates a degree of jaundice characteristic of hyperbilirubinemia for a person having the range of the subject""s particular skin lightness L. L is measured during each subsequent test to be sure that it remains close to the original reading. This gives a degree of confidence that the test procedures are being conducted appropriately.
In the event that the medical condition affecting skin color is detected in a procedure like that described above for hyperbilirubinemia, then the measuring of skin color characteristics continues at regular intervals until the symptomatic color characteristic abates sufficiently to indicate the individual""s recovery from the medical condition. In the case of hyperbilirubinemia, phototherapy is administered once a sufficient change in Hunter b is observed to indicate the jaundice of hyperbilirubinemia. Throughout the course of phototherapy, then, the Hunter b and L characteristics are continually monitored until the jaundice has been eliminated. This is valuable in removing the newborn from under the phototherapy lamps, since there is the danger of damage to the newborn""s eyes in the event eye protection is prematurely removed or accidentally dislodged.
The apparatus used in accordance with this invention includes a color measuring device such as a colorimeter and computational means for storing and comparing the characteristic or characteristics that are measured when testing for the medical condition. Where Hunter b is measured for the purpose of detecting hyperbilirubinemia, a colorimeter capable of calculating Hunter b and L can be used. This can be a commercially available colorimeter with this capability. The computational means preferably has sufficient memory to store one or more previous readings and should be programmed to compare previous and current readings to detect changes in Hunter b and L. Preferably the colorimeter and the computational means are integrated in a single instrument, but the commercial colorimeter can be utilized in cooperation with, for example, a personal computer, which stores and can compare Hunter b and L values from measurements taken at timed intervals. Likewise, the computational means, whether an integrated part of the instrument or a separate computer, can be used to store ranges of lightness L and the increases in Hunter b that, for the various lightness ranges, indicate an unacceptable increase in serum bilirubin.
In one embodiment Hunter a is also measured. The ordinary range of Hunter a for individuals is known. If Hunter a lies outside the ordinary range the reason for this should be determined. If it is because the infant is flushed from crying or has just been washed and rubbed dry the Hunter a is not an indication of a medical problem. If Hunter a is above the ordinary range, but the infant has not been crying, or recently washed or some other non-medical reason, a circulatory problem could be the reason and bears watching to observe if a medical condition is present or phototherapy is in progress. Also, Hunter a sometimes increases just before the jaundice due to hyperbilirubinemia increasing Hunter b. Hunter a, then, may be a warning for closer observation to observe if a medical condition is present or phototherapy is in progress. A decrease in Hunter a along with an increase in both Hunter L and Hunter b such that the ratio of Hunter L to Hunter b remains essentially constant can mean that the infant is anemic and therefore pale, in which case the increase in Hunter b (with a simultaneous increase in Hunter L) would not be indicative of hyperbilirubinemia. The observation of Hunter a then may suggest various medical conditions and it allows one to understand the Hunter L and b readings better and to be more certain whether they are or are not indicative of hyperbilirubinemia.
Preferably, each skin color characteristic measurement used to assess the presence or absence of the condition for which testing is carried out is actually an average of multiple tests. For example, when newborns are tested for the jaundice that signals hyperbilirubinemia, multiple readings are made at multiple sites. Five or six Hunter value readings are made at, for example, each of several locations which may include some or all of a forehead location, at least one chest location, a cheek location and two back locations. Out of range Hunter L, a and b values are discarded. At each site, the Hunter readings that have the highest and lowest values of L, a and b are discarded, then all of the readings of each Hunter characteristic are averaged for each site. Subsequent readings are made in the same manner at exactly the same sites and compared. As used herein, the terms xe2x80x9cHunter a,xe2x80x9d xe2x80x9cHunter b,xe2x80x9d and xe2x80x9cHunter Lxe2x80x9d include such average values, but are not limited to just the values arrived at by the averaging technique unless expressly so-limited. The discarding and averaging is readily accomplished by the computational provisions of the test equipment. The averaging technique may improve the testing of other than skin color where the testing steps of this invention are used, for example in the evaluation of hair by color measurement.
In skin color testing, it is important to cleanse the site utilizing a cleansing agent that does not contribute any coloration. Likewise, when testing is carried out on test subjects other than an individual""s skin, the test subject should be free of any color altering contaminant. In skin color testing, the site on the test subject should be dry, and in all cases the instrument should have the capability of being applied to the site in such a manner that ambient light does not enter the instrument.
In one method according to the invention Hunter L and b are used. Hunter L is monitored for consistency each time measurements are made. The change in Hunter b is monitored for a warning of hyperbilirubinemia. In another method according to the invention Hunter L, a and b are used. Hunter L is monitored for consistency, Hunter b is monitored for a warning of hyperbilirubinemia, and Hunter a is observed for additional information as to the infant""s condition.
Determination of the first and second skin color characteristics, Hunter L and b, at just one point in time can indicate or strongly suggest a medical condition affecting skin color if the first characteristic measurement is observed to lie outside a range of values for that characteristic known by experience to be normal for a subject having the particular measured value of the second characteristic. Again the value of Hunter a should be observed and if abnormal the reason should be sought. For example, in many individuals hyperbilirubinemia is strongly suggested if Hunter b and L are measured and it is determined that, based on skin color categories previously observed, Hunter b is above any ordinary value for a subject with skin having the L value measured. Also, even if baseline readings of Hunter b and L (and preferably a) are not made, changes in the value of Hunter b can nevertheless signal the presence of hyperbilirubinemia if measurements of the Hunter values are made at timed intervals in the foregoing fashion. Out of the ordinary increases in Hunter b, of for example two or more points, can be an indication of hyperbilirubinemia when the measured L value remains in a constant range from one measurement to the next. Similarly, large decreases in Hunter b, of for example two or more points, can be an indication of hyperbilirubinemia from which the infant is recovering, again if L remains relatively constant. If Hunter a changes due to a medical condition such as anemia and the ratio of Hunter L and Hunter b changes, then it is likely necessary to take the anemia into account, for example by using a different change in Hunter b to indicate hyperbilirubinemia or by multiplying Hunter b by a compensatory factor.
Significant testing has established the value of the foregoing techniques in detecting hyperbilirubinemia. The same techniques will indicate other jaundice-producing medical conditions in human and animal subjects. Hepatitis or liver disorders are examples of such medical conditions susceptible to diagnosis with the methods and apparatus of this invention.
Tuberculosis has been observed to affect skin color in dark skinned individuals such as many persons of African descent. Appropriate color measurement in accordance with this invention may provide a valuable diagnostic tool.
Biopsy specimens, body fluids, excretions, etc. are visually inspected for color. The techniques and instrumentation according to this invention can provide objectivity and consistency to such inspections.
According to this invention there is also provided a method and apparatus for accurately characterizing the hair color of individuals to enable identification of the hair color and products suitable to achieve a desired change in hair color, and more particularly to a method and apparatus for measuring color factors in an individual""s hair color to assign that hair color to a classification previously determined to interact with identified hair coloring agents to bring about predictable color changes.
Through experimentation over a prolonged period, the applicants were able to compile a vast amount of information relating to coloration of virtually every imaginable hair color. Thousands of individual hair samples were treated with many various coloring agents. The hair color before and after such treatment was accurately, scientifically measured and characterized using known, reliable color measurement. Hair color was then assembled into a large number of categories based on ranges of the measured color factors. A database was assembled comprising the desired changes available through various hair coloring agents and the particular agents that would effect those changes in human hair to the various categories.
Instrumentation was implemented to measure from an individual""s hair the color factors that operate to place the hair color in one of the numerous hair color classifications and to identify that classification to the individual or the individual""s hair specialist. In addition, the instrumentation was arranged to allow for selection of a desired alteration in hair color, and on the basis of the gathered empirical data, hair coloring agents capable of effecting the desired change were located from within a database.
In an embodiment of the invention, the process for hair color analysis is carried out by measuring with a measuring instrument the value of a number of color factors in the color of an individual""s hair at various sites, and then providing an indicator or table having a large number of hair color classifications defining ranges of those same color factors, and finally comparing the color factors of the indicator or table to the measured color factors to arrive at a classification of the individual""s hair color.
In a preferred embodiment of the invention just described the color factors were Hunter L, a and b.
In an instrumentation implementing the process just described, a colorimeter was used to measure the color factors. The indicator or table having a large number of color classifications was retained in computer memory, and the comparison was made electronically between the memory retained classifications and the measured color factors.
To use the process just described a list or menu of possible choices for varying hair color was presented. Upon selection of that choice, along with the hair color classification as previously determined, is used together with a database of hair color classifications and associated product identifications empirically determined to effect the presented choices of color changes to locate in that database previously tested hair coloring agents capable of effecting the chosen action.
In one further embodiment of the process described, the color factors measured in an individual""s hair color were Hunter L, a and b. Classifications of hair color provided in the indicator or table were percentages of grey in the hair of the individual. This embodiment enables the coloring of grey hair or partially grey hair to obtain an individual""s natural hair coloring or another preferred hair color. This procedure required the selection of one of a number of categories of hair colors such as xe2x80x9clight brown,xe2x80x9d xe2x80x9cdarkest blond,xe2x80x9d xe2x80x9clight red,xe2x80x9d etc. The indicator or table that identified various hair color classifications was divided among broad hair color families or groups of categories, and for an individual the particular hair family division of the indicator associated with that individual""s broad family of hair color was found. The ranges of color factors in that division were then compared with the factors measured in the individual""s hair to arrive at a classification.
In another embodiment of the invention, to arrive at a hair color treatment agent, a database of hair color treatment agents and classifications of color characteristics of individuals was compiled and an individual""s color characteristics were determined by measurement of color factors, followed by comparison of those color factors with ranges contained in the database. In one embodiment the color characteristic of the individual that provided the basis for comparison was skin color.
The above and further advantages of this invention will be better understood with reference to the following detailed description of the preferred embodiments taken in combination with the attached drawings.